Combined resonance of magnetically influenced nanobeam on fractional visco-Pasternak type foundation

Nanostructures with similar shapes as macro structures such as beams, plates or shells are grown using various technological processes. Nano-scale structures mechanical behaviour is similar to macro structures with the main difference that influences of various size-effects cannot be neglected. Particulary, dynamic behaviour of nanostructures is significant for the development of new types of devices such as nanoactuators, nanosensors or resonators. Nonlinear oscillations and dissipation effects from different sources are important for the investigation of nano-scale resonators. Application of experimental and atomistic methods is limited only to specific and less complex nanostructure systems. Modified continuum based theoretical models have attracted a great attention of researchers in recent years. Here, we observe combined parametric and external resonance of a geometrically nonlinear nanobeam resting on a fractional visco-Pasternak type foundation. Euler-Bernoulli beam theory, nonlinear strain-displacement relation and nonlocal elasticity constitutive equation are employed to obtained fractional order governing equation for the transverse vibration of a systems, accounting size effects and dissipation effects from external medium. Under the assumption of small fractional damping, we used the perturbation multiple-scales method to obtain an approximated analytical solution for the frequency-amplitude response in combined parametric and external resonance case for variable axial and transverse loads. Influences of different system parameters on frequency-amplitude response are examined on several numerical examples

Seismic Rehabilitation Techniques for Conserving and Managing Cultural Heritage of old City Fortress in Novi Pazar

In the last decade, increased awareness of the importance of preserving old masonry structures of cultural heritage has turned to the development of sustainable strategies for their reconstruction and seismic strengthening. This research includes the analysis and determination of the necessary measures due to the assessment of the condition of the constructive and structural parts of the buildings belonging to the old City Fortress in Novi Pazar. In this study, the fragility and vulnerability of the building is identified in order to sanction and recommend strengthening and seismic resistance to potentially strong levels of earthquakes, preserving the original structure of the building and its authenticity and integrity. The presented techniques aim to improve seismic performance and preserve structures for future generations, with the least impact on changing the value of the investigated cultural heritage. On the other hand, due to the modern demands of society, it is recommended to implement digital conservation and management of cultural heritage in order to create new content and ensure accessibility for all

New Shape Function for the Bending Analysis of Functionally Graded Plate

The bending analysis of thick and moderately thick functionally graded square and rectangular plates as well as plates on Winkler⁻Pasternak elastic foundation subjected to sinusoidal transverse load is presented in this paper. The plates are assumed to have isotropic, two-constituent material distribution through the thickness, and the modulus of elasticity of the plate is assumed to vary according to a power-law distribution in terms of the volume fractions of the constituents. This paper presents the methodology of the application of the high order shear deformation theory based on the shape functions. A new shape function has been developed and the obtained results are compared to the results obtained with 13 different shape functions presented in the literature. Also, the validity and accuracy of the developed theory was verified by comparing those results with the results obtained using the third order shear deformation theory and 3D theories. In order to determine the procedure for the analysis and the prediction of behavior of functionally graded plates, the new program code in the software package MATLAB has been developed based on the theories studied in this paper. The effects of transversal shear deformation, side-to-thickness ratio, and volume fraction distributions are studied and appropriate conclusions are given

Seismic Rehabilitation Techniques for Conserving and Managing Cultural Heritage of old City Fortress in Novi Pazar

In the last decade, increased awareness of the importance of preserving old masonry structures of cultural heritage has turned to the development of sustainable strategies for their reconstruction and seismic strengthening. This research includes the analysis and determination of the necessary measures due to the assessment of the condition of the constructive and structural parts of the buildings belonging to the old City Fortress in Novi Pazar. In this study, the fragility and vulnerability of the building is identified in order to sanction and recommend strengthening and seismic resistance to potentially strong levels of earthquakes, preserving the original structure of the building and its authenticity and integrity. The presented techniques aim to improve seismic performance and preserve structures for future generations, with the least impact on changing the value of the investigated cultural heritage. On the other hand, due to the modern demands of society, it is recommended to implement digital conservation and management of cultural heritage in order to create new content and ensure accessibility for all

Thermal Buckling and Free Vibration Analysis of Functionally Graded Plate Resting on an Elastic Foundation According to High Order Shear Deformation Theory Based on New Shape Function

Functionally graded square and rectangular plates of different thicknesses placed on the elastic foundation modeled according to the Winkler-Pasternak theory have been studied. The thermal and mechanical characteristics, apart from Poisson’s ratio, are considered to continuously differ through the thickness of the studied material as stated in a power-law distribution. A mathematical model of functionally graded plate which include interaction with elastic foundation is defined. The equilibrium and stability equations are derived using high order shear deformation theory that comprises various kinds of shape function and the von Karman nonlinearity. A new analytically integrable shape function has been introduced. Hamilton’s principle has been applied with the purpose of acquiring the equations of motion. An analytical method for identifying both natural frequencies and critical buckling temperature for cases of linear and nonlinear temperature change through the plate thickness has been established. In order to verify the derived theoretical results on numerical examples, an original program code has been implemented within software MATLAB. Critical buckling temperature and natural frequencies findings are shown below. Previous scientific research and papers confirms that presented both the theoretical formulation and the numerical results are accurate. The comparison has been made between newly established findings based on introduced shape function and the old findings that include 13 different shape functions available in previously published articles. The final part of the research provides analysis and conclusions related to the impact of the power-law index, foundation stiffness, and temperature gradient on critical buckling temperature and natural frequencies of the functionally graded plates

A Literature Review of Parameter-Based Models for Walkability Evaluation

Many scientific papers that deal with the topic of the pedestrian environment use a predefined form for assessing or evaluating its quality as a basic methodological instrument. The aim of this research is to emphasize the dimension of the available audit tools or methodologies in order to develop a full-scale database of indices that can be used for the measurement and evaluation of the pedestrian environment. By analyzing 115 research papers selected according to predefined selection criteria, the basic methodological apparatus or the evaluation instrument was observed. Based on the analysis carried out in this way, a number of 40 valid instruments were identified by which it was possible to evaluate the pedestrian environment. The observed instruments have a high level of reliability according to the high values of the ICC coefficient, IRR test, or Kappa value. There are 193 items for the evaluation of the pedestrian environment that were derived from the observed instruments. The items were arranged over seven groups regarding the quality of the pedestrian environment, namely, Functionality, Safety, Comfort, Mobility, Environment, Connectivity, and Aesthetics. On average, the items distributed over those seven groups are in use throughout the entire pool of instruments at the level of 47.41% across all groups. There are 30 instruments or methodologies that are objectively based, 4 subjectively oriented, and 6 with elements of both approaches. Of the instruments, 14 measure and assess the pedestrian environment through a quantitative data set, while 20 are designed for qualitative assessment. Only six of the instruments contain both qualitative and quantitative measuring items. A large percentage of analyzed papers that use a predefined methodology or instrument indicate the need to deepen the field of research and to include additional aspects that would give more authoritative results